A winter freeze can kill tender seedlings, damage roots, and ruin plant foliage. It is vital that gardeners protect plants against frost before spring and shortly before a fall freeze. When temperatures are expected to drop considerably, protecting your plants from freezing conditions is essential for saving them from the ravages of cold weather.
Frost protection is usually needed in the early spring. Warm sunny days can suddenly drop below 32°F (0°C) after sunset. A sudden change in the weather in fall can cause a hard frost on the ground. And since climate patterns are changing, surprise frosts are becoming more frequent.
A simple frost cover can provide protection for tender growing plants; other protective plant covers can include cloches, mulch, blankets, or specific frost covers for plants; and for many potted plants, it is best to protect them by bringing them indoors.
A comprehensive guide to protecting your vegetables, flowers, seedlings, fruit trees, and shrubs from damage caused by frost is presented in this article. You will also learn which frost covers are most effective and how to use them.
What Is Frost?
Plants suffer frost damage when low temperatures cause the water inside their cells to freeze. Frost-damaged leaves have limp, black, and shriveled appearances. Frost-damage can be observed in the form of limp, black, and shriveled leaves on plants. As ground and plant surfaces are covered with the surface frost, it appears like a fine dusting of sweet sugar.
The ground temperature must be at the freezing point for frost to form – 32°F (0°C). The sun typically warms the ground so frost occurs at night. Ice can destroy many plants and, in extremely extreme circumstances, root vegetables can freeze and rot.
By using a frost cover, for example, you can guard your plants against freezing because water will not be able to fall on foliage, resulting in fewer frost spots on leaves. The covers also maintain the ground just above freezing point when frost occurs.
At What Temperature Do Plants Freeze
In the coldest conditions, plants can freeze within five hours when the air temperature falls below 28°F (-2°C). However, different freezing conditions affect plants differently. Many tender annual plants and seedlings are damaged by frost when temperatures drop below 32°F (0°C), but some plants can survive at temperatures as low as 18°F (-7.7°C).
Hardiness zones determine what temperatures the plant or vegetable can survive down to. For example, plants in zones 4 through 7 on average can survive up to the freezing point, but they are usually sensitive to extremely cold conditions and need protection.
When to Expect Frost
Frost typically occurs when the air temperature is below 32°F (0°C), there are clear skies, and the wind speed is below 10 mph (4 m/s). Cool, calm conditions, combined with a lack of cloud cover, make frost an ideal climatic condition.
When preparing for a frost event, it’s important to keep a close eye on weather forecasts. The National Weather Service issues forecasts in advance whenever frost is expected.
Frost Advisory is issued during the growing season when minimum temperatures are between 33°F and 36°F (0.5°C – 2°C) overnight, and the night is clear and calm.
There is a Freeze Watch in effect if the minimum temperature falls below 32°F (0°C) over the next couple of days.
When widespread freezing temperatures are expected during the fall and growing season, a Freeze Warning is issued.
When temperatures are expected to drop below 28°F (-2°C) for an extended period, a Hard Freeze Warning is issued.
How to Protect Plants from Freezing
When there is a frost advisory warning, make sure plants are protected by covering them with blankets or sheets. Then, you can temporarily cover all the plants in the morning with a plastic cover to prevent the heat from escaping. This will help prevent the risk of freezing the following night.
You can protect a plant’s root system from hard freeze by covering it with heavy mulching. Pile hay or wood mulch on top of the soil to shield it from cold temperatures. You can also place mason jars filled with warm water every evening inside the mulch to remain warm.
Protect your shrubs and vegetables from extreme cold by creating a burlap fence around them. Fill the fence section with hay, place jugs of warm water inside, and cover it with burlap. Remove the fence during warm days or when the hard freeze is over.
How to Protect Flowers from Frost
If you are ready to protect your flowers from frost, include household items, such as bed linens, upturned cardboard boxes, buckets, and flower pots. For example, bed sheets can provide insulation for flowers, which helps keep them from contact with the cold air.
You can buy frost blankets for plants, but you might already have items in your home that you can use to make your own frost covers.
Wrapping Trees for Winter
Wrapping young trees around the trunk and branches protects against frost and ice damage and prevents winter sun damage. Deer are also kept away from your trees because of the protective wrap.
Wrap the tree trunk and lower branches loosely with a breathable material, such as burlap, to help protect the tree from winter and early spring frost damage.
The trunk of a tree may be burned if the daytime sun is too warm. Wrap the trunk in reflective white guards if sun scald is a concern.
How to Cover Plants for Frost
Plant covers are a good way to protect plants from a frosty chill. Keep them handy for use when a surprise frost occurs. In addition to handmade plant covers, you can use boxes, buckets, rags, linens, and towels. Be sure to secure the plants with stakes or rocks so the covers won’t blow away. Be sure that a plastic cover never touches your plants’ foliage if you are using it as frost protection.
The Best Frost Covers for Plants
You don’t need elaborate equipment to cover your plants against frost. The goal of the frost cover is to prevent air vapor from settling on the foliage or ground when it’s near freezing temperature. You can use many everyday items to protect plants against frost.
In case of a serious chill early in the year or late in the year, here are the best methods of covering plants.
For protection from bitter cold, frost row covers make excellent choices. These plastic row covers let moisture in but stop heat from escaping. You will have to stake or frame the plastic to keep it off your plants.
A bedsheet is a simple DIY solution for covering plants in frosty conditions. You can drape the bedsheet over the pot and secure it with bricks to keep the plants protected. If you expect a lot of frost, you can use a warm blanket.
The easiest way to protect plants from cold weather is to place inverted buckets over them after a frost advisory is issued. Use a heavy object to secure the buckets in place. You can use flower pots to protect plants during a brief icy spell.
If the bottom of plastic bottles can be cut off, you can use them as cloches that protect plants from frost, and then place them over the soil over each plant.
If you are using frost covers, you should remove them during the day and put them back after dusk in order to allow your tender new plants to get as much warmth energy as they need.
How to Protect Plants from Frost
Plant protection from frost is necessary in temperate climates, especially in the winter and in early spring. Aside from covering plants, what other ways can you take to guard your plants? Here are some useful tips.
Water Soil in the Afternoon Before Frost
Maintaining the soil damp in early spring ensures excellent protection from frosts. Remember, a light frost doesn’t penetrate into the soil so the water can’t freeze. Moisture radiates heat after the sun sets, so a well-watered garden is a good idea if you anticipate nights that are chilly.
During the afternoon, when the temperatures are the warmest, water the ground to protect plants from frost. Even if you decide to cover plants, the moist soil, which creates a warm environment, will allow plants to grow in spite of the frost.
Add a Thick Layer of Mulch
A layer of mulch in early spring will shield plants from a brief frost. Mulching around tender plants will insulate the ground and prevent sudden temperature changes. You can protect your garden from frost with mulch made from hay, wood chips, bark, leaves, and evergreen branches.
Some perennials are more susceptible to freezing in winter when their roots are heavily mulched.
To make mulch effective as a frost blanket, follow a few guidelines. First, leave an inch or two around the plant’s central stalk. This allows heat to escape from the soil. Additionally, remove most of the mulch after the frost threat has passed.
The use of mulch in gardening is beneficial throughout the year because it can keep soil moist and control weeds.
Bring Potted Plants Inside
Potted perennials should be brought inside during cold snaps to avoid damage to foliage and roots. Putting them in a garage, shed, or similar structure can eliminate frost damage. On warm spring days, you can bring them out on your patio, backyard, or deck.
Container plants need to be protected from frost when brought indoors. First, do not bring them into warm rooms, as the sudden temperature change can stress them. Second, tender potted plants are susceptible to frost since they are not protected by insulating soil.
Grow Plants in Frost-Resistant Locations
If you have seeds or potted plants that are more susceptible to frost injury, elevating them above the ground can help prevent frost injury. Frost likes to form on flat surfaces, so it is important to keep plants elevated above the ground.
If you live in a west- or south-facing building, you could also place potted flowers or hanging baskets against the walls. During the day, the building absorbs heat, then releases it at night, keeping your plants warm.
The method is good for an unexpected, short cold snap, but it is not recommended for long-term use.
Grow Cold-Hardy Plants That are Frost Resistant
It is possible to find plants that grow despite hard frosts and extreme cold temperatures, as well as cold-hardy cultivars which are specially bred to withstand harsh weather conditions and snow. During the winter, some hardy flowering perennials die down to the ground, but frost does not affect the roots, and they begin to grow again in spring.
Young trees can survive the cold winter and spring by being wrapped in reflective wraps or burlap. Wrapping fruit trees is particularly important as their thin bark is easily damaged by frost. Loosely tie wrapping around the trunk from the ground to the first branches.
If there is a freeze warning, secure plant rows with burlap, blankets, bed linen, or mulch when the temperature drops to 32°F or 33°F (0°C – 0.5°C). Add a layer of plastic on top for extra insulation.
How to Protect Succulents from Frost
It depends on the type of succulent if you need protection from frost. Some succulent varieties are cold-hardy to zone 5. In fact, many desert plants can tolerate hot sunny days and freezing nights.
The best way to grow succulents in pots outdoors during the summer is to place them in a sheltered location indoors if there’s a danger of frost or ice.
What to Do After the Risk of Frost has Passed?
When the risk of a sudden cold snap in spring has passed, you can start planting your spring garden. You can transplant seedlings you have been growing indoors into flower beds and vegetable plots. You can also prune shrubs and bushes for healthy growth and lots of blooms.
Spring weather can quickly change, and it is easy to be caught by a surprise frost. But plant covers are still a good idea for emergencies.